STRESS CALCULATIONS

[GEOR99]

I am trying to determine how to calculate if there is enough material between the bore of a gear and the root of the tooth. The gear is a 24T spur gear, the O.D. is 6.768", the pitch is 4DP(25pa), the bore is 4.250", the width is 4.63", and the RPM is 363. Does anyone know where to locate the appropriate formulas?

 

[GEOR99]

Also, The torque is 200,000 in-lbs.

 

[ecampos]

The equation is mb=tr/ht
where mb is "backup ratio", tr is "gear rim thickness below the tooth root (in.)" and ht is "gear tooth whole depth (in.)"
Without you having the graphs in front of you, if mb is less than 1.2, than you are at risk of stress failure through the rim and need to increase the thickness of "tr".
The info is from AGMA 2001-C95 pg. 11, and annex B.
Simply iterate until you get a value of "mb" over 1.2

Edson Campos
edsoncampos@earthlink.net